Weight gain is a common side effect that accompanies adjuvant chemotherapy for breast cancer. While the phenomenon of weight gain is consistent, the magnitude is greater among patients who receive multi-agent, high dose regimens and among those who are younger (25 percent of premenopausal patients gain over 11 kg during treatment). Patients report weight gain as "distressing" There also is evidence that weight gain adversely affects disease-free survival, and predisposes women to cardiovascular disease and diabetes. Chemotherapy-induced weight gain also is distinct - patients lose muscle as they gain adipose tissue, thus calling for interventions that promote exercise. In a preliminary study, we found that losses in muscle and gains in fat can be prevented if patients participate in a clinic-based program that promotes specific exercises and a low fat, high vegetable and fruit diet during the time they receive treatment. While these data are encouraging, few patients participated due to barriers of travel. Since many cancer patients travel long distances to receive care, the purpose of this R21 application is to ascertain whether home-based exercise interventions are feasible using the framework of the cooperative group (Cooperative Community Oncology Program (CCOP)) and show promise for further testing in a larger group setting, such as the Cancer and Leukemia Group B (CALGB). We have adapted our program that was based in a state-of-the-art fitness facility to portable gym equipment, and have developed accompanying materials (i.e., videotapes and manuals), as well as a program of telephone counseling. We also have obtained the support of the Wake Forest Research Base CCOP to help us ascertain whether a home-based exercise program bears promise and is feasible to implement and test using the infrastructure of the cooperative group. We propose a study that will measure the effects of an exercise alone or exercise plus diet intervention on preventing weight gain and adverse changes in body composition, reducing depression, improving quality of life and influencing biomarkers associated with breast cancer and other co-morbid conditions (i.e., insulin, insulin-like growth factor-i, sex hormone binding globulin and lipoprotein profiles). We propose a pilot study where these endpoints will be assessed at baseline and 6 months post-diagnosis in 90 premenopausal early stage breast cancer patients who will receive adjuvant chemotherapy and are block randomized into 1 of 3 study arms (attention control, exercise alone or exercise plus diet). If data show promise, further and larger study will be pursued - study which will be focused on testing an optimal intervention and powered on known effect sizes.